Pitt Cosmologists Part of New Project to Create Largest-Ever Map of Universe

Issue Date: 
March 21, 2011

Pitt’s prolific cosmology group in the School of Arts and Sciences’ Department of Physics and Astronomy will again lend its expertise to a multi-institutional endeavor to investigate the distant universe, further expanding Pitt’s role in the most ambitious efforts to unravel the inner workings of deep space.

The National Optical Astronomy Observatory (NOAO)—the R&D arm of the National Science Foundation that oversees ground-based astronomy—recently granted conditional approval for the BigBOSS Collaboration to observe the universe for 500 nights using one of the world’s largest telescopes, the Mayall 4-meter Telescope housed in Arizona’s Kitt Peak National Observatory. A pivotal first step, NOAO’s approval means that BigBOSS can now move into the final design stage, said Jeffrey Newman, a Pitt assistant professor of physics and astronomy, who joined the project shortly after it was conceived in 2009 and was involved in the crucial proposal to NOAO.

Led by the U.S. Department of Energy’s Lawrence Berkeley National Laboratory, BigBOSS—or the Big Baryon Oscillation Spectroscopic Survey—will peer back into the past 10 billion years of the universe’s lifespan to find precise locations for almost 20 million galaxies and quasars. The project gets its name from baryon acoustic oscillations, which are the leftover imprint of sound waves that moved through the early universe when it was hot and dense. This imprint causes galaxies to bunch up at roughly 500-million-light-year intervals. This unique signature provides a high-precision test of the nature of the mysterious dark energy that is causing the universe to expand at an ever-accelerating rate.

The linchpin of the project is a massive new instrument, the BigBOSS spectrograph, capable of studying the light from 5,000 galaxies or stars at one time. Observations captured with the spectrograph—roughly 10,000 of them—will then be compiled into the largest map of the universe ever created. The next steps for BigBOSS are to secure funding, construct the spectrograph, and, with luck, begin observations as early as 2017, Newman said.

Five Pitt cosmologists will take part in BigBOSS, constituting one of the largest contingents of scientists from a single institution after the Berkeley Lab, Newman said. Joining Newman are professors Arthur Kosowsky and Regina Schulte-Ladbeck, assistant professor Michael Wood-Vasey, and assistant professor Andrew Zentner.

The Pitt team will take on various projects within BigBOSS, including using the resulting data to study the nature of dark energy and the development of galaxies over time, identifying the particular galaxies and quasars the survey should investigate, and developing new methods and tools to handle the immense data processing requirements and huge databases that will result from BigBOSS. This last objective will draw on the department’s collaboration with Pitt’s Department of Computer Science and the Pittsburgh Supercomputing Center.

Pitt’s involvement in BigBOSS also sustains the University’s long involvement in large-survey astronomy that began in 1994 with the most influential survey project, the Sloan Digital Sky Survey (SDSS). Pitt cosmologists now help lead or participate in approximately a dozen different projects that document the active lives of celestial bodies—from colliding galaxies and tremendous explosions to star-gobbling black holes—in an effort to better understand cosmic objects and the universe’s evolution.

These projects include: SDSS III (Wood-Vasey), an international effort to better understand dark energy, the structure of planetary systems, and the genesis of the Milky Way; CANDELS (Newman), the longest single project ever carried out with the Hubble Space Telescope; and the half-billion-dollar Large Synoptic Survey Telescope (Kosowsky, Newman, Wood-Vasey, and Zentner), a 14-year collaboration between 23 institutions to construct the world’s largest digital camera (with 3 billion pixels) to record the movement and development of the universe over 10 years in a color movie of the sky.